Several techniques for positioning medical devices in the cardiovascular systems of patients have been previously proposed in the pertinent art. In many instances, the object of these techniques is to advance a tool into the artery of a patient which is capable of accomplishing a desired task inside the artery. For example, in many of today's surgical procedures, medical devices such as catheter mounted angioplasty balloons, incisors, stents and artherectomy cutters are routinely introduced into patient's cardiovascular systems in accordance with prescribed protocols. One commonly used apparatus for introducing these devices is a guidewire.
Typically, whenever a guidewire is used for the purpose of introducing a medical device into the cardiovascular system of a patient, the guidewire is pre-positioned in situ. Normally this is done through an introducer sheath or an introducer catheter which is used to establish an access site into the cardiovascular system of the patient. The catheter mounted medical device is then subsequently advanced through the introducer (guiding catheter) and over the guidewire. During the advancement of the catheter over the wire, however, it is extremely important for the physician to maintain positive control over both the stability of the guidewire and the advancement of the catheter. Further, it is important that the means for controlling the stability of the guidewire and the means for controlling the advancement of the catheter be relatively close to each other and relatively near the introductory access site into the patient.
One solution to the control problem for an over-the-wire catheter is to provide a guidewire of sufficient length so that any extracorporeal portion of the guidewire is longer than the catheter that is being introduced over the wire. This, however, can be cumbersome and may require manipulation of the system at a substantial distance from introductory access site. A solution to this problem has been the use of so-called monorail catheters. The monorail catheters in use today have a relatively short guidewire lumen which is located near the distal tip of the catheter so that the guidewire can be extracorporeal separated from the catheter. This arrangement, however, still requires the physician to effectively control both the guidewire and the catheter.
In light of the above, it is an object of the present invention to provide an over-the-wire catheter system which effectively reduces the physician's control requirements to only advancement of the catheter. Another object of the present invention is to provide an over-the-wire catheter system which stabilizes the position of the guidewire during advancement of the catheter over the wire. Still another object of the present invention is to provide an over-the-wire catheter system which incorporates the guidewire, the introducer, and the catheter into a cooperative system which allows for accurate placement of the catheter into the cardiovascular system of a patient. Yet another object of the present invention is to provide an over-the-wire catheter system which is simple to use, relatively easy to manufacture, and comparatively cost effective.